Big Bore Cylinder Kit Yz 250 21009-K01Big Bore Cylinder KitCylinder kit includes matching Vertex pistons to ensure longevity, performance and reduced engine noise Cylinders have a nickel silicon carbide cylinder sleeve Look virtually identical to OEM cylinders Kit includes cylinder, pistons, rings, pin, clips and gaskets Made in the USA Cylinder does not require machine work (unless noted). Kit Includes: Cylinder Cylinder Head Power Valve Kit Piston Kit Top End Gasket Kit Wrist Pin